Method to improve flowability of alkaline phenolic resin coated sand

Abstract

A process for improving the flowability of resin coated sand which comprises the use of a flow promoter with the mixture of sand and resin. Also provided is a foundry mix comprising foundry sand, a resin binder and the flow promoter, as well as a process for making foundry cores and molds using the foundry mix. The resins are ester-curable alkaline phenolic resole resins. The flow promoter is selected from the group consisting of fatty acids, fatty alcohols, fatty amines, fatty amides and fatty alkanolamides.

What is claimed is: 
     
       1. A process for improving the flowability of sand coated with an alkaline phenolic resole resin binder curable by a volatile ester in a "cold box" process which comprises incorporating in the mixture of sand and resin binder an amount of flow promoter effective to improve the flowability of the mixture wherein said flow promoter comprises one or more compounds having the structural formula: A-Y where A is a hydrocarbon radical containing from about 10 to about 20 carbon atoms and Y is selected from the group consisting of --OH, --COOH, --OZ, --NR 2  and --CONR 2  where the Rs are the same or different and denote H, alkyl groups containing from 1 to 3 carbon atoms, or Z, where Z denotes --(CHX--CHX--O) n  H wherein X denotes H or CH 3  and n is a whole number from 1 to 5. 
     
     
       2. The process of claim 1, wherein the amount of flow promoter is from about 0.01 percent to about 5 percent by weight of the resin binder. 
     
     
       3. The process of claim 2, wherein the amount of flow promoter is from about 0.1 percent to about 2 percent by weight of the resin binder. 
     
     
       4. The process of claim 1, wherein the flow promoter is added to the resin binder before it is coated on the sand. 
     
     
       5. The process of claim 1, wherein the flow promoter and resin binder are added separately to the sand. 
     
     
       6. A foundry mix for preparing foundry cores and molds which comprises a foundry sand, from about 0.5 percent to about 8 percent by weight of the sand of an alkaline phenolic resole resin binder curable by a volatile ester in a "cold-box" process and an amount of a flow promoter effective to improve the flowability of the mix wherein said flow promoter comprises one or more compounds having the structural formula: A-Y where A is a hydrocarbon radical containing from about 10 to about 20 carbon atoms and Y is selected from the group consisting of --OH, --COOH, --OZ, --NR 2  and --CONR 2  where the Rs are the same or different and denote H, alkyl groups containing from 1 to 3 carbon atoms, or Z, where Z denotes --(CHX--CHX--O) n  H wherein X denotes H or CH 3  and n is a whole number from 1 to 5. 
     
     
       7. The foundry mix of claim 6, wherein the amount of flow promoter is from about 0.01 percent to about 5 percent by weight of the resin binder. 
     
     
       8. The foundry mix of claim 7, wherein the amount of flow promoter is from about 0.1 percent to about 2 percent by weight of the resin binder. 
     
     
       9. A process for the production of foundry cores and molds which comprises: (a) preparing a foundry mix of claim 6;   (b) placing the foundry mix in a vented core or mold box; and   (c) gassing the mix in the core or mold box with a volatile ester.   
     
     
       10. The process of claim 9, wherein the foundry sand used to prepare the foundry mix is selected from the group consisting of silica sand, chromite sand, zircon sand, olivine sand and mixtures thereof. 
     
     
       11. The process of claim 10, wherein the aqueous alkaline solution of a phenolic resole resin binder used to prepare the foundry mix is present in an amount of about 1 percent to about 3 percent by weight of the sand. 
     
     
       12. The process of claim 11, wherein the flow promoter used to improve the flowability of the mix comprises from about 0.01 percent to about 5 percent by weight of the binder. 
     
     
       13. The process of claim 12, wherein the flow promoter comprises from about 0.1 percent to about 2 percent by weight of the binder. 
     
     
       14. A foundry core or mold prepared by the process of claim 9.